The invention relates to an electromagnetically actuated valve system and to a combined valve device.
An electromagnetically actuated valve system for ensuring different functions is known from European Patent document EP 0 305 710 A2. The combination of such valve systems, i.e., a first electromagnetically actuated valve system and a second electromagnetically actuated valve system, to form a combined valve device is also revealed in that patent document. In this case, the two are integrated in a jointly usable housing. The first electromagnetically actuated valve system is used for controlling the connection between a pressure medium source and a consuming device or a consuming device arrangement, that is, a plurality of consuming devices, whereas the second valve system is used for controlling the pressure relief of the consuming device or the consuming device arrangement.
The two valve systems of the combined valve device preferably have an identical construction in order to achieve a high degree of standardization with respect to the further development of the individual elements. The first valve system has an inlet chamber, which can be connected with the pressure medium source by way of a corresponding connection, and a working chamber, which can be connected with a consuming device or a consuming device arrangement. A main valve is arranged between the two chambers. This main valve consists of a movable valve member and a valve seat fixed to the housing. In addition to the inlet chamber and the working chamber, a pilot chamber and a compensation chamber are provided in the housing of the first valve system.
For controlling the movement of the main valve member, a control element is provided. The control element is constructed such that it is acted upon by the inlet pressure on a first surface assigned to the inlet chamber in the opening direction of the main valve, while the pressure in the pilot chamber is applied to a second surface of the control element assigned to the pilot chamber in the closing direction of the main valve. In this case, the second surface is larger than the first surface. The pilot chamber can be connected with the working chamber by means of a pilot valve. The pilot valve is formed of a movable pilot valve member and a pilot valve body connected with the armature of the actuating magnet.
The main valve member and the pilot valve member are fixedly coupled in such a manner that a movement of the main valve member in the opening direction of the main valve is simultaneously a movement of the pilot valve member in the closing direction of the pilot valve. The pilot chamber is connected with the inlet chamber by means of a throttle connection. The throttle connection is dimensioned such that, when the opening cross-section of the pilot valve is small, this throttle connection permits at least an identically large pressure medium throughput into the pilot chamber as the pilot valve out of the pilot chamber and, when the opening cross-section of the pilot valve increases, a lower pressure medium throughput into the pilot chamber than the pilot chamber valve from the pilot chamber.
The second valve system, which preferably is constructed analogous to the first valve system with respect to the control element, the actuating device and the method of operation of the main valve and the pilot valve, has a working chamber connected with the consuming device system, which, when the valve device is combined, simultaneously represents the outlet chamber of the first valve system, and an outlet chamber connected with an outlet between which a main valve is arranged. The main valve consists of a valve seat fixed to the housing and a movable main valve member, the outlet being connected at least indirectly with a pressure relief space. Furthermore, analogous to the first valve system, a control device controlling the movement of the main valve and a pilot chamber are provided. The control element is acted upon by the consuming device pressure on a first surface assigned to the working chamber in the opening direction of the main valve. On a second surface assigned to the pilot chamber, the control element is acted upon by pressure in the pilot chamber in the closing direction of the main valve. In this case, the second surface is also larger than the first surface. The pilot chamber can be connected with the outlet chamber by means of a pilot valve. The pilot valve is formed by a movable pilot valve member and a pilot valve body connected with the armature of the actuating magnet. In this case, the main valve member and the pilot valve member are fixedly coupled in such a manner that a movement of the main valve member in the opening direction of the ma in valve simultaneously is a movement of the pilot valve member in the closing direction of the pilot valve. The pilot chamber is connected by way of another throttle connection with the outlet chamber, that is, in this case, the relief chamber.
The valve systems disclosed in this document require high constructive expenditures and intensive mounting. In particular, the constructions according to European Patent document EP 0 305 710 A2 contain a control system with a valve and a switching piston at the ends. In this case, the thinner part of the control device is guided through a partition For ensuring the power transmission, the individual components are riveted tom one another. The construction of the control device increases the required space for the individual valve system. Furthermore, it is impossible with respect to a valve system according to the above-mentioned document to check the valve seats without destroying the individual valve systems or the combined valve, device. The replacement of the elastic valve seat of the main valve also causes high expenditures. During repairs or servicing, damage to other—originally not affected parts—cannot be excluded. The maintenance of this valve system is therefore risky. For this reason, in the event of damage—irrespective of the extent of the damage—, it is therefore always recommended that the complete valve system or even the complete valve device be exchanged.
Another embodiment of a combined valve device is contained in European Patent document EP 0 145 858. This document has openings in the control piston, which openings are monitored by means of a magnetic valve. By means of the 3/2-magnetic valves, the control chambers can be joined to the input pressure or to the pressure which is in each case situated on the output side.
From European Patent document EP 0 095 782, a compact control valve for hydraulic precision control is known, which comprises a pilot valve and a main valve; however, the main valve member simultaneously forms the valve seat for the pilot valve body; that is, the pilot valve member. The two are coupled with one another with respect to their function; particularly, the actuating of the main valve simultaneously causes an actuating of the pilot valve. The valve seat of the main valve is formed by a housing bore in which the pilot valve member is guided. Repairs require the complete demounting of the valve device. Damage to the main valve seat requires an exchange of the entire device.
The construction according to German Patent document DE 39 31 761 A1 involves a valve system comprising a pilot valve which is spatially separated by an insert having control and connection bores and can be functionally coupled with one another by way of this insert. Although this solution has the advantage of a simple exchangeability of the two mutually coupled valve systems, exchange and servicing operations always require a complete demounting of the individual valve system—relay valve or control valve.
It is therefore an object of the invention to provide a valve system and, particularly, a combined valve device for the sensitive control of the connection between a pressure medium source and a consuming system, as well as for controlling the pressure relief of the consuming system, which valve system and valve device is mounting-friendly and maintenance- or repair-friendly. While the fluid throughput and, particularly, the air throughput remains the same or is increased, the required constructional volume is to be reduced. Another aspect consists of the easy manufacturing of the elements of the individual valve systems and, particularly, of the combined valve device. The requirement concerning the repair-friendliness includes the possibility of checking the quality of valve pairings, so that, when the finding is positive, a continued use of the already operating valve pairings should be possible. When an exchange is required, only the defective parts would then have to be replaced while the undamaged components remain in use.
The solution according to the invention is characterized in that the pilot chamber is assigned to the main valve member such that the main valve member, at least in a partial area of its surfaces oriented in a mutually opposed manner viewed in the flow direction of the pressure medium, is in each case acted upon by the pressure existing in the inlet chamber and the pressure existing in the pilot chamber. The pilot chamber is connected by way of at least one connecting duct extending through the structural element forming the main valve member with the inlet chamber. The structural element, which forms the main valve member, and the pilot valve member are free of a constructional coupling with one another. The stationary seat of the main valve is formed by an insert, which can be clamped into the housing of the valve system. The pilot valve member is formed by the insert, which can be clamped into the housing of the valve system or by the housing, the connection between the pilot valve and the outlet chamber taking place by way of at least one connecting duct arranged in the housing or in the insert. A combined valve device has a first valve system, particularly an electromagnetically actuated valve system, characterized in that the inlet chamber can be connected with a pressure medium source, and the outlet chamber forms a working chamber which can be coupled with a consuming device, and a second valve system, particularly an electromagnetically actuated valve system, characterized in that the inlet chamber is formed by a working chamber, which can be coupled with a consuming device, and the outlet chamber can be connected with a relief space. Advantageous further developments are in each case indicated in the subclaims.
The electromagnetically actuated valve system comprises an electromagnetic actuator; a main valve member which is arranged between an inlet chamber and an outlet chamber and has a main valve member and a stationary valve seat; furthermore, a pilot chamber which is connected with the outlet chamber by way of a pilot valve. The pilot valve comprises a valve element and a valve body which is connected with an armature of the electromagnetic actuator, which armature is linked with an actuating magnet. The main valve member and the pilot valve member are free of a mutual constructional coupling; that is, that a movement of the main valve member in the opening direction of the main valve in comparison to a valve system of the above-mentioned type, is not simultaneously a movement of the pilot valve member in the closing direction of the pilot valve. The main valve member is formed by a structural member which is also called a closing body. According to the invention, the stationary seat for the main valve member is formed by an at least two-part insert, which can be arranged in the housing of the electromagnetically actuated valve system. By means of corresponding sealing devices, the closing body, together with the insert and possibly the housing, forms the pilot chamber, the pilot chamber being arranged such that the pressure therein acts upon the main valve member on the face pointing away from the inlet chamber. The coupling between the inlet chamber and the pilot chamber takes place by way of at least one axial duct extending through the closing body. The pilot valve member is formed by an at least two part insert, which can be clamped into the housing of the valve system, or by the housing, the connection between the pilot valve and the outlet chamber taking place by way of at least one connecting duct arranged in the housing and/or in the insert.
The pilot chamber has a pressure-medium tight construction with respect to the inlet chamber and outlet chamber. The two valves of the valve system—the main valve and the pilot valve—are arranged parallel or side-by-side, that is, in two parallel planes.
By means of providing the at least two-part insert, the assignment of the pilot chamber to the closing body and the construction of the connecting ducts in the functional elements, that is, in the closing body forming the main valve member and in the insert or housing part forming the pilot valve member, a valve system is created which is easy to mount and demount and which simultaneously is very servicing- and repair-friendly, in which case it does not necessarily have to be expected that adjacent structural elements will be damaged during the demounting. Since the construction of the surfaces required for generating the valve pairings takes place on different elements, an exchange of the defective components can be carried out independently of the further utilization of the other valve pairings. Because of the very compact method of construction in the axial direction, that is, in the inflow direction viewed from the inlet or the inlet chamber, and the combination of the functional units in a very narrow space, the required constructional volume could be considerably reduced while the fluid throughput, particularly the air throughput, remains the same or is increased.
The electromagnetically actuated valve system designed according to the invention is suitable for implementing many different tasks. Corresponding to the arrangement in pneumatic circuits or the assignment to individual elements of such a circuit, this valve system can be used either as
1) a control valve for controlling the connection between a pressure medium source and of a consuming device (which is not shown), or as
2) a pressure relief valve for controlling the pressure relief of one consuming device or several consuming devices.
In the former case, the inlet chamber can be coupled with a pressure medium source, while the outlet chamber operates as a working chamber and is coupled with a consuming device. In the latter case, the inlet chamber is formed by the working chamber which is coupled with a consuming device while the outlet can be connected with a relief space.
Under another aspect of the invention, it is, however, also possible to assign a valve system designed according to the invention to an arbitrary convention valve system such that either the task mentioned in 1. or the task mentioned in 2. is carried out by the valve system.
The two valve systems are preferably combined in a combined valve device for carrying out the two above-mentioned tasks. In this case, the construction and the design of the individual elements of the main and pilot valves preferably take place in an identical manner. This has the advantage that a high degree of uniformly designed component elements is produced, which is advantageous particularly also when individual elements have to be exchanged, since the storage is reduced because of the small number of structural elements. For this purpose, two electromagnetically actuated valve systems designed according to the invention are combined in a housing, which has three connections, specifically an intake which can be coupled with a pressure medium source; a discharge which is at least indirectly coupled to a consuming device; and a relief connection which is at least indirectly connected with a relief space. For this reason, the discharge of the first valve system and the intake to the second valve system are formed by a joint connection to the consuming device; that is, one connection is utilized jointly. On the one hand, this combined valve system is used for controlling the connection between the intake from the pressure medium source to the consuming device and, on the other hand, for controlling the pressure relief in the working chamber coupled with the consuming device. The two valve systems have an identical construction with respect to the actuator and the closing body. However, differences exist with respect to the inserts in the joint housing because the boundary between the two valve systems is not formed by the housing wall but by the insert or one of the inserts. The inserts preferably have multipart constructions for each valve system in order to permit an easy mounting and demounting of the individual elements of the valve system, particularly of the closing body. The closing body itself is constructed as a piston element which, for forming the main valve, has an end area which is widened in a piston-type manner and which in each case, corresponding to the type of valve system, is acted upon on its face—first valve system or second valve system—by the pressure in the inlet chamber or by the pressure in the working chamber. The connection between the inlet chamber and the pilot chamber takes place by a duct extending in the axial direction through the closing body. This duct is therefore used for forming a constant throttle in the inlet area into the axial duct at the closing body. As a result of the corresponding actuation of the pilot valve body, which is coupled with an armature element of the electromagnetic actuator, a controllable throttle is formed which is connected behind the constant throttle.
The two valve systems—the first valve system and the second valve system—each have an electromagnetic actuator. This actuator comprises at least one actuating magnet, which is connected with an armature. The armature, in turn, is at least indirectly, preferably directly, connected with the valve body of the pilot valve device. With respect to the method of operation and thus the achieving of the individual functional positions of the pilot valve device of each valve system, essentially the following two possibilities are available:
1. Selection of an actuating magnet with an ascending stroke/current characteristic; that is, the valve body is pulled into the corresponding functional position.
2. Construction of the actuating magnet with a descending stroke/current characteristic; that is, implementation of the functional positions of the valve body by pressure.
When combining the two valve systems in a combined valve device, the two valve systems are preferably used with an identical actuator so that the positions required for the implementation of the method of operation of the combined valve system are implemented either by energizing or non-energizing an individual armature element. The utilization of this possibility has the advantage that the degree of standardization for the further development of such valve systems for different application purposes and a use in a combined valve device can be increased considerably. This has the additional advantage that, in the event of a possibly required exchange, particularly in the case of combined valve systems, no attention has to be paid to different actuators.
The concrete further development of the individual elements of the individual valve systems may also take place differently. However, preferably at least the closing body is constructed symmetrically with respect to an axis. The closing body is constructed as a piston element; that is, as an element which has different dimensions in the cross-sectional view. For forming the pilot chamber and for an easy mounting and demounting, the insert is constructed in several parts, preferably in two parts.
A plurality of possibilities exists with respect to the construction of the inserts. In the case of a construction as an individual valve system, that is, with only one closing body and one actuator, these inserts preferably have a symmetrical construction for being used between an intake and a discharge. In the simplest case, a two-part construction is also selected here. In this case, the partial insert element, which is first in the inflow direction from the intake, forms the valve seat of the main valve. For forming the pilot chamber, a sealing device is provided between the face of the closing body directed away from the intake in the area of the formation of the main valve, which sealing device rests against this surface, and is fastened to the insert, either on the first partial insert element or on the second partial insert element. This sealing device is preferably constructed as an elastic membrane. Sealing devices are preferably also provided between the main valve seat and the surfaces on the main valve member, which enter into an operative connection with the main valve seat. These sealing devices may be arranged either on the stationary valve seat or on the closing body. The arrangement preferably takes place on the closing body.
When the insert is constructed in two parts, the second partial insert element, viewed in the inflow direction from the intake, is arranged behind the first and forms additional boundary walls of the pilot chamber. The connection between the pilot valve and the outlet takes place by way of corresponding passage openings in the housing or at the insert, preferably the first and the second partial insert element outside the area of the pilot chamber.
In the case of the construction as a combined valve device, that is, the combination of the two valve systems and the assignment to the three above-mentioned connections, the further development of the inserts takes place such that here also a degree of standardization is achieved which is as high as possible; that is, the proportion of the elements with an identical construction is as high as possible.
The embodiment is particularly advantageous in the case of a combined valve device, in which the membrane used for forming the pilot chamber extends over both valve systems and thus is arranged, for example, clamped, between the first and the second partial insert element of the inserts for the first and the second valve system. For connecting the individual pilot valves with the corresponding outlets, that is, the first pilot valve device with the working chamber and the second pilot valve device with the relief space, at least one corresponding opening is provided in the sealing device, for example, in the form of passage openings.
In the case of a construction or combination of two valve systems designed according to the invention to form a combined valve system with three connections, according to another aspect of the invention, the valve system can be supplemented by additional structural elements in order to carry out additional functions. The integration of devices for detecting a condition parameter, particularly of the pressure in the working chamber to the consuming device, for example, is conceivable in this case. As a rule, this is implemented as a pressure sensor. It is advantageous that, by a coupling with the corresponding electronic system, particularly the linkage to or integration in a control device, this condition parameter, particularly the pressure, can be regulated.
A further development consists of, in addition to the pressure sensor, integrating an electronic control device in the combined valve system. This integration permits the creation of a compact, easily mountable and repair-friendly pressure control module, which can be offered as a completely merchantable unit.
The solution according to the invention will be explained in the following by means of figures.